Techniques for detecting degrees of awakening of people have conventionally been proposed. As such a technique, Patent Document 1 discloses a technique which captures an image of an eyeball part of a person, extracts a pupil area of the eyeball part from the captured image, and judges that the degree of awakening is lowered when the time and frequency of blinks are found to be not less than predetermined values according to changes in the extracted shape of the pupil (Patent Document 1: Japanese Patent Application Laid-Open No. 6-270711).